XC2287 / XC2286 / XC2285
XC2000 Family Derivatives
Preliminary
Functional Description
3.4
Interrupt System
With an interrupt response time of typically 8 CPU clocks (in case of internal program
execution), the XC228x is capable of reacting very fast to the occurrence of non-
deterministic events.
The architecture of the XC228x supports several mechanisms for fast and flexible
response to service requests that can be generated from various sources internal or
external to the microcontroller. Any of these interrupt requests can be programmed to
being serviced by the Interrupt Controller or by the Peripheral Event Controller (PEC).
In contrast to a standard interrupt service where the current program execution is
suspended and a branch to the interrupt vector table is performed, just one cycle is
‘stolen’ from the current CPU activity to perform a PEC service. A PEC service implies a
single byte or word data transfer between any two memory locations with an additional
increment of either the PEC source, or the destination pointer, or both. An individual PEC
transfer counter is implicitly decremented for each PEC service except when performing
in the continuous transfer mode. When this counter reaches zero, a standard interrupt is
performed to the corresponding source related vector location. PEC services are very
well suited, for example, for supporting the transmission or reception of blocks of data.
The XC228x has 8 PEC channels each of which offers such fast interrupt-driven data
transfer capabilities.
A separate control register which contains an interrupt request flag, an interrupt enable
flag and an interrupt priority bit field exists for each of the possible interrupt nodes. Via
its related register, each node can be programmed to one of sixteen interrupt priority
levels. Once having been accepted by the CPU, an interrupt service can only be
interrupted by a higher prioritized service request. For the standard interrupt processing,
each of the possible interrupt nodes has a dedicated vector location.
Fast external interrupt inputs are provided to service external interrupts with high
precision requirements. These fast interrupt inputs feature programmable edge
detection (rising edge, falling edge, or both edges).
Software interrupts are supported by means of the ‘TRAP’ instruction in combination with
an individual trap (interrupt) number.
Table 4 shows all of the possible XC228x interrupt sources and the corresponding
hardware-related interrupt flags, vectors, vector locations and trap (interrupt) numbers.
Note: Interrupt nodes which are not assigned to peripherals (unassigned nodes), may
be used to generate software controlled interrupt requests by setting the
respective interrupt request bit (xIR).
Data Sheet
41
V0.91, 2007-02
Draft Version
INFINEON [ Infineon ]
